The present invention relates to a snubber circuit for suppressing voltage spikes applied to a power semiconductor device in a power converter using the power semiconductor device as a switching element. More particularly, the present invention relates to an improved snubber circuit for a power semiconductor device which can be reduced in size.
In a conventional snubber circuit of this kind, a diode, a resistor and a capacitor, or a Zener diode and a capacitor are connected in series, and the series circuit is connected in parallel to a power semiconductor device, the device to be protected, so that a spike voltage is suppressed by a current charged to the capacitor. In such a snubber circuit, however, a transient forward voltage of 30 to 60 V is applied while the diode is turned on and the voltage rises to 60 to 100 V due to the wiring inductance of the snubber circuit until the circuit provides a snubber function. In addition, separate parts such as a diode, resistor and capacitor are connected to each other, making reduction in size difficult and introducing inductance which slows down operation.
Accordingly, it is an object of the present invention to provide a snubber circuit for a power semiconductor device which can remove the above-described problems in the prior art.